Electric switch



June 8, 1943. P. M. ENGEL ELECTRIC SWITCH Filed Feb. 5, 1942 Inventor: I Philhp M. Engel,

Hi5 Attorney Patented June 8, 1943- ELECTRIC SWITCH Phillip M. EngeL-Lansdowne, Pa, assignor to General Electric Company, a corporation of New York Application February 5, 1942, Serial No. 429,623

7 Claims. (01. 200-169) My invention relates to improvements in electric switches and more particularly disconnecting switches and especially high' current capacity disconnecting switches which have electrically and physically parallel spaced blades and which may, in some cases, be subjected to intense shocks.

Any current carrying loop is subjected to a magnetic force efiect which tends to straighten the loop. This magnetic straightening eiTect is greater the smaller the effective radius of curvature of the loop and also increases with increase in the current conducted by the loop. The usual type of knife blade switch involves a current conducting loop. If the switch has to conduct large currents, then it is likely to be forced open, particularly when the circuit in which it is connected is subjected to a fault causing currents of short circuit magnitude. Inasmuch as such switches are not designed to interrupt currents of anysubstantial magnitude, great damage may result if a switch should open under such conditions. Moreover in times of stress it may be desirable to operate such switches at current values great enough to cause their unintended opening. This difficulty is further accentuated since in confined spaces it is necessary to use short blades. This means a current conducting loop of relatively small effective radius of curvature and consequently increased magnetic straightening effect. Furthermore, if in addition to this effect there is imposed a shock effect, the resultant of the two efiects is quite likely to cause an opening of the switches with not only the attendant hazards but also an interruption inservice at a most critical moment.

An object of my invention is to provide an improved electric switch which can be positively maintained in the circuit closing position even when subjected to shocks while conducting large currents and also regardless of the efiective radius of curvature of the current loop through the switch. Another object of my invention is to provide a simple, effective and economical locking means which can readily be applied to disconnecting switches of the knife blade type and which also embodies a handle operating structure similar to that heretofore used. These and other objects of my invention will hereinafter appear in more detail.

In accordance with my invention, I provide a switch locking mechanism comprisingrelatively fixed and movable locking members, one of which can be rotated to effect movement thereof transversely of themovable conducting members of the switchinto locking engagement with the other locking member whereby positively to lock the switch in a predetermined circuit controlling position. Further in accordance with my invention, I provide a switch locking means which is incorporated in and forms a part of the handle structure of the switch.

My invention .will be better understood from the following description when considered in connection with the accompanying sheet of drawings, and its scope will be pointed out in the appended claims.

In the accompanying sheet of drawings, Fig. 1 shows in side .elevation an electric switch embodying my invention; Fig. 2 is a front elevation of the embodiment of my invention shown in Fig. 1;Fig. 3 is an elevation to an enlarged scale of the embodiment of my invention shown in Figs. 1 .and 2 with parts broken away for clearness in illustration and with the mechanism in the locked position; Fig. 4 is a partial elevation similar to Fig. 3 with the locking mechanism in the released or unlocked position; and Fig.5 is a sectional view on the line 5--5 of is- The disconnecting switch illustrated in Figs. '1 and 2 is a three-pole high empere capacity switch of the knife blade type. As shown, this switch comprises a base lil of suitable insulating material on which are mounted two spaced terminal blocks II and I2 for each pole. As

shown, eachof the terminal blocks H has two spaced tongues i3 which constitute the stationary contacts. Also, each of the terminal blocks I 2 has two tongues it. These tongues constitute hinge member on which the movable contacts or blades i5 are pivotally mounted for rotation about a common axis, indicated by the broken line it, through the aligned pivot bolts ll. The hinged mounting of the blades includes suitable contact pressure applying means, such as cupped spring washers l8. As shown, each pole of theswitch 'includestwo pairs of spaced parallel blades, although more or less may be provided depending on the current capacity desired. Whether the blades are grouped in pairs or a single blade with a jaw type stationary contact is used has-no bearing on my invention. Also, as far as my invention is concerned, it will be obvious that the number of poles is immaterial. The blades of each pair are secured at their free ends bya bolt l9 and cupped spring washers 20 so as to insure the desired contact pressure on the tongues I3, which are suitably notched to permit entry of the bolts. In order that the blades l5 may be operated simultaneously from one circuit controlling position to another, they are rigidly interconnected by a common transverse member, such as a cross bar 2| of insulating material to which the four blades of each pole are fastened by suitable means, such as yoke members 22.

Associated with the blades so as to be movable therewith are two spaced supports 23 which, as shown, are suitably secured to the cross bar 2| and extend outwardly therefrom on the side away from the free ends of the blades l5. In accordance with my invention, I provide means for locking the blades l5 in a predetermined circuit controlling position which in the illustrated embodiment of my invention is the circuit closing position. As shown, this locking means comprises a shaft 24 which is rotatably supported on the supports 23. The rotatable supporting means comprises two locking members 25 and 26 which are axially movable on and rotatable with the shaft 24. For this purpose, the end portions of the shaft 24 may be square, as shown more clearly in Fig. 5, to engage a square opening in the locking members. Each of the looking members 25, 26 and the support on which it is mounted have cooperating means for effecting axial movement of the locking member relatively to the shaft 24 upon rotation of the shaft.

As shown, this means comprises interlocking screw threaded means in each support and on the locking member mounted therein. Since it is desirable to have both interlocking members 25 and 26 moved outwardly into locking position simultaneously and, also, simultaneously withdrawn to the unlocking position, the members 25 and 2t and their supports may be pivoted with leftand right-handed threads respectively on the two supports.

For engagement by the locking members 25 and 26 positively to lock the blades l5 in the circuit closing position, I provide two stationary locking members 21 and 23 which are positioned for locking engagement by the movable locking members 25 and 26 upon rotation of the shaft 24 while the blades i5 are in the circuit closing position. For this purpose, the stationary locking members 2! and 28 are provided with registering openings into which the movable locking members 25 and 26 project when the shaft 24 is turned in a predetermined direction and from which the movable locking members are withdrawn when the shaft is turned in the opposite direction. For readily turning the shaft, I provide on the square end portions thereof one or more circular shaped members 29 which may be knurled or otherwise provided with means for firmly grasping and turning by hand.

In order to provide a handle for readily operating the shaft, I mount on the shaft 24 a hollow circular member 30 which may be of insulating material. The handle 30 is preferably rotatably positioned on the shaft and may be spaced therefrom by a sleeve 3| which provides a cylindrical support for the handle 30 in case the shaft 24 is square throughout its length and which is suitably secured to the shaft 24 so as to rotate therewith. The length of the sleeve 3| is preferably such as to insure that the rotating members 29 cannot engage the handle 39 at the ends. This prevents the possibility of rotating the locking members in the turning movement or the handle during the opening and closing movements of the switch.

Referring now in particular to Fig. 2, it will be observed that the movable locking members 25 and 26 are in interlocking engagement with the stationary locking members 2! and 28. Upon rotation'of one of the rotatable members 29 in the correct direction, the shaft 24 will be rotated to effect the turning of the movable locking members 25 and 26 and the consequent withdrawal of these members from their cooperating stationary locking members 21 and 28. When this is done, the handle 30 may be grasped to swing the blades to the circuit opening position. When it is desired to close the switch and lock it in the closed position, the reverse procedure is followed.

It will be observed from Figs. 1 and 2 and Fig. 1 in particular that the effective radius of curvature of the current loop through each pole of the switch is small and that the switch is of high current carrying capacity. Consequently, the magnetic effect tending to straighten the loop is large. However, because of the positive looking means provided by my invention, the switch is definitely maintained in the closed position regardless of the magnetic loop straightening effect and, also, regardless of any shocks which add to this effect by tending to release the blades.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangement shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of th United States is:

1. An electric switch comprising relatively movable cooperating contacts, two spaced supports extending from one of said contacts and means for locking said one of said contacts in a predetermined circuit controlling position comprising a shaft, means rotatably supporting said shaft on said supports comprising two locking members respectively rotatably mounted on said supports and axially movable on and rotatable with said shaft, each locking member and the support on which it is mounted having cooperating means for effecting axial movement of the member relatively to the shaft upon rotation thereof and two stationary locking members positioned for looking engagement by said movable locking members upon rotation of said shaft while said on of said contacts is in the predetermined circuit controlling position.

2. An electric switch comprising a plurality of stationary contacts, a plurality of spaced switch blades mounted for movement into and out of engagement with said contacts, a transverse member rigidly interconnecting said blades, two spaced supports on said transverse member, and means for locking said blades in a predetermined circuit controlling position comprising a shaft extending transversely of said supports, two movable locking members axially slidable on said shaft and rotatable therewith, said locking members being respectively rotatably mounted on said supports and each locking member and the sup port on which it is mounted having cooperating means for effecting rectilinear movement of the locking member upon rotation thereof, and two stationary locking members positioned for looking engagement by said movable locking members upon rotation of said shaft while said blades are in a predetermined circuit controllin position.

3. An electric switch comprising a plurality of stationary contacts, a plurality of spaced switch blades mounted for movement into and out of engagement with said contacts, a transverse member rigidly interconnecting said blades, two spaced supports on said transverse member, and means for locking said blades in the circuit closing position comprising a shaft extending transversely of said supports, two movable locking members axially slidable on said shaft and rotatable therewith, said locking members being respectively in screw threaded engagement with said supports whereby to effect rectilinear movement of the locking members upon rotation thereof, and two stationary locking members positioned for locking engagement by said movable locking members upon rotation of said shaft in one direction while said blades are in the circuit closing position.

4. An electric switch comprising relatively movable cooperating contacts, one of said contacts comprising a plurality of electrically and physically parallel and relatively closely spaced blades, two spaced supports extending from said one of said contacts and means for locking said blades in the circuit closing position comprising a shaft, means rotatably supporting said shaft in said supports comprising two locking members respectively in right and left handed screw threaded engagement with said supports and axially movable on and rotatable with said shaft upon rotation thereof and two stationary locking members positioned for locking engagement by said movable locking members upon rotation of said shaft in one direction while said blades are in the circuit closing position.

5. An electric switch comprisin a plurality of stationary contacts, a plurality of spaced parallel switch blades pivoted for movement about a common axis into and out of engagement with said contacts, a cross bar rigidly interconnecting the free ends of said blades, two spaced supports extending from the side of the cross bar opposite the free ends of said blades, and means for looking said blades in the circuit closing position comprising a shaft extending transversely of said supports, two movable locking members axially slidable on said shaft and rotatable therewith, said locking members being respectively in right and left handed screw threaded engagement with said supports whereby to effect movement of the locking members upon rotation thereof, and

two stationary locking members positioned for locking engagement by said movable locking members upon rotation of said shaft in one direc tion while said blades are in the circuit closing position.

6. An electric switch comprising relatively movable cooperating contacts, supporting means extending from one of said contacts, and means for locking one of said contacts in a predetermined circuit controlling position comprising a shaft, means rotatably supporting said shaft on said supporting means comprising a locking member rotatably mounted on said supporting means and axially movable on and rotatable with said shaft, said locking member and the supporting means on which it is mounted having cooperating means for efiecting axial movement of the mem-- ber relatively to the shaft upon rotation thereof, and a stationary locking member positioned for locking engagement by said movabl locking member upon rotation of said shaft while said contacts are in the predetermined circuit controlling position.

7. An electric switch comprising cooperating contacts, one of which is mounted for movement into engagement with the other, and means for locking said one of said contacts in a predetermined circuit controlling position comprising two spaced supports, a shaft, means rotatably mounting said shaft on said supports comprising two locking members respectively rotatably mounted on said supports and axially movable on and r0 tatable with said shaft, each locking member and the support therefor having cooperating means for effecting axial movement of the member relatively to the shaft upon rotation thereof, and two members positioned for locking engagement by said locking members upon rotation of said shaft while said one of said contacts is in a predetermined circuit controlling position.

PHILLIP M. ENGEL. 

